Vehicle Inertia Measuring Machine
Date of issue: May 2016
www.cfm-schiller.de
Vehicle Inertia Measuring Machine
The VIMM is a fully automatic measuring system which determines the 10
parameters of inertia of a specimen within one single measuring cycle. These
parameters of inertia consist of the mass of the test item, the center of gravity
in X-, Y- and Z-direction, the moments of inertia Ixx, Iyy and Izz and the products
of inertia Ixy, Iyz and Ixz.
Definitions:
Center of gravity (CoG)
is the physical point at which all external forces and moments are acting on.
Moment of inertia
is a physical value, which in mechanics specifies the inertia of a rigid body
with respect to its rotation. It is equivalent to the mass in parallel translations.
It depends on form, distribution of mass and the axis of rotation of a body.
Mechanical construction VIMM
2
Vehicle Inertia Measuring Machine
Product of inertia (centrifugal moment)
is a physical value, which can be understood as the urge of a rotating body
to change its rotation axis. Occurs when a body does not rotate around of its
main inertia axis or one of the parallel axis. Products of inertia and moments
of inertia are combined to form the inertial tensor. The VIMM is mainly used
to determine the CoG and inertia parameters of a vehicle. These parameters
are required for simulation of the dynamic handling during the development
of a vehicle as well as for the development of electronic stability controls.
Furthermore they are used to assess the roll-over behavior of new vehicles.
This is particularly relevant on the North American market, as the NHTSA
(National Highway Traffic Safety Administration) carries out a rollover safety
rating. The VIMM can also be used to analyse other components and
assemblies concerning the above mentioned parameters. This merely involves
dismantling the ramps of the standard system.
VIMM peripherie
System Mechanics - Design
The base frame consists of a steel construction with a platform that is
attached via a special cardan joint. This platform represents the core element
of the VIMM. The VIMM has three hydraulic actuators that perform the roll,
yaw and pitch movements. If smaller components are measured, it makes
sense to dismantle the ramps and to utilize the mounting table above the
central joint.
The ramps are designed such that the vehicle is positioned in lateral direction.
The alignment in parallel to the longitudinal can be done by sliding plates
underneath the wheels. This allows the manual alignment of the longitudinal
axis (x) of the vehicle, as well as the position on the leteral axis (y).
The vehicle is fixed by using sill clamps in order to prevent any influence
(elasticity) of the wheel suspension and tires during measurement.
In order to fix the platform in neutral position, a locking system with electrical
actuation is integrated into the base frame.
Sensors
The main sensorset of the VIMM consists of 3 load cells. The load cells for
the z-direction are integrated within the central joint and on top of the lateral
hydraulic actuator. The front central joint has an integrated 3-axis load cell.
Furthermore, the roll, yaw and pitch angles are measured by angle encodes
integreated in the central joint. In addition, linear transducers are integrated
in the actuators, which serve as a redundant monitoring system.
Measuring Process
The vehicle is driven onto the VIMM the centre of gravity ist positioned in
x-direction (longitudinal axis of the vehicle) and in y-direction (lateral axis of
the vehicle) is located above the central joint.
This minimizes the inaccuracies incurred by the eccentric mass.
3
Produkte
The test specimen has to be positioned and fixed on the VIMM. No modification is required during the measuring process. The location of the centre
of gravity is determined in vertical direction with a quasi static rolling
movement around the x-axis, aided by the lateral hydraulic actuators.
The position of the platform is detected by incremental encoders integrated
within the central joint.
In the following step of the measurement, the dynamic roll, yaw and pitch
movements are carried around the respective axes. During these movements
the values of the force and incremental encoders are recorded, and the
required moments and products of inertia are calculated using mathematical
algorithms. The inertia parameters are thus determined automatically in one
single test cycle without having to perform any further modifications.
Sill clamp
4
Prüfstandssysteme
Vehicle Inertia Measuring
Machine
KEY benefits
•
Significant saving of time due to one single test cycle
•
Total time for measurement including installation 2,5h
•
High accuracy and reproducibility of the test results
•
Calibration on site is possible
•
Test cycle is easy to handle
•
10 inertia parameters will be measured fully automatically using VIMM
•
No motification of the test setup required
•
Easy positioning of the vehicle, as the measuring device can be driven
Software VIMM
onto the VIMM
•
The system can be used to measure components and assemblies
•
Real time operating system
•
Excellent economical and energy balance
5
Produkte
key data
•
Max. load capacity 3.500 kg
•
Maximum accuracy for centers of gravity up to 800 mm above the central joint
•
Wheel base: 1.800-4.350mm, track width: 1.200-2.100 mm
•
Total weight of the mechanical system: approx. 2.500 kg
•
Required electrical connection power: 45KW, 400V, 3 Phase + PE + N
•
Required hydraulic performance: 90l/min at 210 bar
•
Required space for the VIMM
Pit measuring: 4.700 x 3.500 x 1.750mm
•
Measurement accuracy:
In the measurement range following accuracies are valid:
COGx,y,z: <±5 mm
Ixx,yy,zz: <±4% at values >500 kgm2, at values <500 kgm2 <±20 kgm2
Ixy,yz,xz: <±4% at values >500 kgm2, at values <500 kgm2 <±20 kgm2
Note: Measurement accuracy increase parallel to the increase of rigid body characteristic of
the real test specimen.
VIMM configuration for components testing
6
Prüfstandssysteme
Vehicle Inertia Measuring
Machine
The VIMM was developed in cooperation with the Institut für Kraftfahrwesen, IKA, of the RWTH Aachen/Germany (Rheinisch- Westfälische Technische
Hochschule), and has been patented since 2006.
The VIMM is unique in its function and design. The aim of the design
and development was to create a system which is able to fully automatic
determine all ten inertia parameters, whilst also keeping a tight on the
production and development costs.
The VIMM is an outstanding combination of cost-efficiency and functionality.
We would like to convince you:
If you would like to see the system in operation, please come and visit us on
our premises and let us demonstrate the functionality and effectiveness of
the VIMM, in our test laboratory. To help you make a decision for acquiring
such a system, why not bring your own vehicle to make comparative
measurements? Our service, your advantage!
Talk to us and make an appointment with our systems and sales engineers.
We are looking forward to answering any questions you may have and helping
you to make the right choice for your business.
Sill clamp & Hydraulic cylinder
Further details on request.
7
HEADQUARTER:
Germany
CFM Schiller GmbH
[email protected] | www.cfm-schiller.de
SALES OFFICES:
Belgium | Netherlands | Luxemburg
AKRON n.v.-s.a.
[email protected] | www.akron.be
Sweden
Kvalitest Sweden
[email protected] | www.kvalitest.com
Brasil
Signalworks Comércio
[email protected] | www.signalworks.com.br
Turkey
Vibration Isolation Systems for electrodynamic shakers
[email protected] | www.starteknik.com.tr
China
CFM Schiller China | Michael Zhao
[email protected]
Turkey
Test Rig Components
[email protected] | www.megadanismanlik.com.tr
Finland
Kvalitest Nordic Oy
[email protected] | www.kvalitest.com
USA
CFM-ITBona LLC | Bernd Ruttkowski
[email protected] | www.cfm-itbona.com
France
CFM Schiller France | Gérard Lacazette
[email protected]
Germany
Sale north and east germany| Veronika Runzer
[email protected]
Germany | Austria | Switzerland
Sale south | Alexandra Wierzba
[email protected]
Great Britain
PES (UK) Limited
[email protected] | www.pesukltd.com
India
CFM Schiller India Engineering Pvt Ltd.
Sandeep Vidwans | [email protected]
México
Grupo CTT S.A. de C.V.
[email protected] | www.grupoctt.com.mx
Poland
Elhys Sp. z o.o. | Michal Jablonski
[email protected] | www.elhys.com.pl
Spain
SEM, SA
[email protected] | www.semsa.es
CFM Schiller GmbH | Special machine construction, specialized in vibration isolation and test bench systems | Managing director: Dipl.-Ing. Wolfgang Peters
Print: CFM Digitaldruck | [email protected] | www.cfm-digitaldruck.de
Subject to errors, printing errors and technical modifications. All earlier editions are invalid.